Mechanically compensated zoom lens system

ABSTRACT

A mechanically compensated zoom lens system consisting of two movable lens groups, each lens group consisting of four airspaced lens elements.

.sau-wao SR I United State [1113,630599 [72] Inventor Roscoe J. Donne] [56] References Cited [2]] A l N 2:22;" UNITED STATES PATENTS pp o. [22] Filed on 21,1970 3,143,590 8/1964 Higuchi 350/184 [45] Patented Dec. 28, 1971 Primary Examiner- David Schonberg [73] Assignee Xerox Corporation Assia'tant Examiner- Paul A. Sacher Stamford, Conn. Attorneys-James J. Ralabate, Franklyn C. Weiss and Irving Keschner [54] MECHANIC-ALLY COMPENSATED ZOOM LENS SYSTEM 5 Claims, 4 Drawing Figs.

[52] U.S. Cl 350/184 [5 1] Int. Cl. G02!) 15/14 ABSTRACT: A mechanically compensated zoom lens system [50] Field of Search. 350/184, consisting of two movable lens groups, each lens group con- 186 sisting of four air-spaced lens elements.

MECHANICALLY COMPENSATED ZOOM LENS SYSTEM This invention relates to zoom lens systems. More particularly, this invention relates to a mechanically compensated zoom lens system suitable for use as a copying lens.

An example of a mechanically compensated zoom lens system is disclosed in U.S. Pat. No. 3,030,863 and an example of a copying lens is disclosed in U.S. Pat. No. 3,439,976.

It is an object of this invention to provide a new and improved zoom lens system.

It is another object of this invention to provide a new and improved mechanically compensated zoom lens system.

It is still another object of this invention to provide a zoom lens system that can be used as a copying lens.

It is yet still another object of this invention to provide a zoom lens system that has low distortion, a flat field, no vignetting, high resolution and nearly equal finite conjugates.

It is another object of this invention to provide a mechanically compensated zoom lens system that is achromatic over the spectrum of 4,000 A to 5,000 A, has a magnification range of 1.000 to 0.6500, has a relative aperture off/11.8 over a field of view of about 44, is compact, has high resolution and low distortion and is suitable for use in a copying machine having fixed rigid object and image separation.

The above and other objects are achieved by constructing a zoom lens system according to this invention. Briefly, the zoom lens system is made up of two movable lens groups, with each lens group consisting of four air-spaced lens elements.

A clearer concept of the scope and purpose of the invention along with various advantages and features thereof will be obtained from the following detailed description taken in conjunction with the drawings in which:

FIG. I is an optical diagram of one embodiment of the invention;

FIG. 2 is a chart of constructional data for the embodiment shown in FIG. 1;

FIG. 3 is an optical diagram of another embodiment of the invention; and

FIG. 4 is a chart of constructional data for the embodiment shown in FIG. 3.

Referring now to FIG. I, the lens system as a whole is designated by reference numeral 11. the object plane of the lens system is designated by reference numeral 12 and the image plane of the system is designated by reference numeral 13. As can be seen, the lens system 11 is made up of two movable lens groups, the front lens group being identified by reference numeral 21 and the rear lens group being identified by reference numeral 22. Each lens group is made up of four air-spaced lens elements. Lens group 21 is made up ofa negative meniscus shaped element A convex to the front, a negative meniscus shaped element B convex to the front, a negative meniscus shaped element C convex to the front and a positive meniscus-shaped element D convex to the front. Lens group 21 is made up ofa first double convex element E, a double concave element F, a negative meniscus shaped element G concave to the front and a second double convex element H. A diaphragm 31 is positioned between element E and element F.

In FIG. 2 and repeated below for convenience is a chart of constructional data for the lens system shown in FIG. 1.

Referring now to FIG. 3. the lens system as a whole is designated by reference numeral 41, the object plane of the lens system is designated by reference numeral 42 and the image plane of the system is designated by reference numeral 43. As can be seen, the lens system 41 is made up of two movable lens groups, the front lens group being identified by reference numeral 51 and the rear lens group being identified by reference numeral 52. Each lens group is made up of four air-spaced lens elements. Lens group 51 is made up of a negative meniscus shaped element A convex to the front. a negative meniscus shaped element 8 convex to the front, a negative meniscus shaped element C convex to the front and a positive meniscus shaped element D convex to the front. Lens group 52 is made up of a first double convex element E, a first double concave element F, a second double concave element G and a second double convex element H. A diaphragm 61 is positioned between element E and element F.

In FIG. 4 and repeated below for convenience is a chart of constructional data for the lens system shown in FIG. 3.

CHART I Nd at V at Group Lens Radius Thickness Spacing 4,500 A. 4,500 A.

22.5474 at 1.0000 S 25.0864 at 0.8062 26.3680 at 0.6600 R1=6.3587 A t1=0.4416 1. 0027 40.

Sg=0.2l23 R;=4.3689 B t; =0.6705 1, 6562 27. 8.! 21 R =3J436 R =2.4209 C ls=0.5781 1. 5904 5.. 67

R=232243 S =0,2112 R7=2.7-116 D t,=0.4485 1. 6850 33. 03

R =4.9682 0,2006 at 1.0000 S 0.4556 at 0,8062 Rn=4,0243 1.1885 at 0.6600 E ls=0.8307 1. 6344 II 37 Rm= S.1247

Ss =0.1941 S: =0.1731 R 3,7706 F le=0.321!l 1. 6437 30. J0

R11 =5A137 22 s,=0.5024

Ru= 10,5610 G tr =0.2556 1. 6278 42.16

8 0,0211 R =21 ,9775 H ts=0.6498 1. 6636 -17. 23

R s=3.5022 26,0552 at 1,0000 1o= 232960 at 0,8062 20.7550 at 0.6500

No'rEs -F.O.V.=44; F,/#=F/11 8; Zoom mangificution ronge=l 000, to 0.6500; E.F.L.=From 13.3585

12,7476. All dimensions are in inches.

CHART II Nd at V- at Group Lens Radius Thickness Spacing 4,500A. 4,500 A.

22.3261 at 1.0000 s'.= 242461 01.0.8500 R, 62336 26.1064 M06500 1 A R, 36346 t =0.4572 1.0027 40.55

S'z=0.2860 R==4.1518

13:11am 1. 6562 27.212 R'.=3.4555 51 s'.=0.1s0s

R',=2.s07o c R, In z'.=0.5104 1.5004 52.07

S4=0.3680 R1=3.2701 D R 48119 '.=0.3002 8 0000 1.0550 33.63

a= 0,505 at 1. B .29.. 01-00030 9 R, u t' =0,7614 1. 6344 10. 3?

s'.=0,2734 s'1=0.14s0 R1l=4,5438 1'1=0 2102 1. 0437 30. 00

s',=0.0202 R'..=13,0s45 H =0 g575 1. 6030 47. 23

RIF-3.0800 25.0704 at 1.0000 SI1Q= 21,8673 111:0.8500 20.7003 0110,6500

-F-0- .=44; F/#=F/11.8; Zoom ma nification an c=1000 to 0.6500 E.F.L.=F1-0m 13 t0 12.7803. All dimensions are in inches. 8 r g x CHART III Nd at V at Group Lens Radius Thickness Spacing 4,500 A. 4,500 A.

22.2626 at 1.0000 S; 25,1462 at 0,7700 R 6 02 20.3023 at 0.6500

1 A R 3 5374 t1=0.4574 1. 6027 10.55

S: =0.2645 R; =3 7587 B l'z=0.5002 1. 0562 27. 82

R4 =3,1209 51 S; =0.l.l33

R; =2,4784 C' R 2 3720 t;=0 4481 1. 5004 52. G7

S. =0.3651 R; =3,1881 D R 4 t =0,3244 1.6850 33. 63

0.4004 at 1.0000 S; 0,8540 at 0.7700 R 4 4909 1.6478 at 0,6500

0 E t'5=0j8353 1. 0344 40. 37

S, =0,1722 S; =0.1830 R||= 4.2271 F l0=0..'277-1 1. 6437 30. 00 52 B. =4,8518

R'1a= 11,447-l G l =0,'2810 1. 6278 -12, -16

Sn =0.0206 R =18 6167 H lx=0,7365 1. 6636 47. 23

26,0475 at 1.0000 '1u= 22.7102 at 0,7700 7602 at 0 6500 NOTE,F.0.V,=3B;F/#=F/lLS; Zoom magnification 1'mig0=1,000x to 0.66001; E.F.L =F1-0n1 13,4105 to 12,7807. All dlmenslons are in inches,

In all of the charts, the radii of curvature R of the lens elelens elements and the Abbe numbers v ofthe lens elements are ments. the thicknesses 1 of the lens elements. the spacings s all e pressed in the customary mannerbetwecn the lens elements. the index of refraction Nd of the What is claimed is:

l. A mechanically compensated zoom lens system consisting essentially of an axially movable front lens group and an axially movable rear lens group. each lens group consisting essentially of four air-spaced elements, the front lens group con- 3. A mechanically compensated zoom lens system consisting essentially of an axially movable front lens group and an axially movable rear lens group. each lens group consisting essentially of four air-spaced elements. the front lens group consisting essentially of, from the front to the rear, a first negative 5 sisting essentially of, from the front to the rear. a first negative meniscus convex to the front, a second negative meniscus conmeniscus convex to the front, a second negative meniscus convex to the front, a third negative meniscus convex to the front vex to the front, a third negative meniscus convex to the front and a positive meniscus convex to the front and the rear lens and a positive meniscus convex to the front and the rear lens group consisting essentially of, from the front to the rear a first group consisting essentially of, from the front to the rear a first double convex element, a double concave element. a negative double convex element. a first double concave element, a meniscus element concave to the front and a second double second double concave element and a second double convex convex element. element.

2. A mechanically compensated zoom lens system made 4. A mechanically compensated zoom lens system made substantially according to the following specifications: substantially according to the following specifications:

Group Lens Radius Thickness Spacing Nd at V zit 22.5474 at 1.0000 s,= 25,0864 at 0,8062 26.8680 at 0.6500 R,=6.35s7 A 1 =0.1410 1. 6027 40. 55

s =0 212s Ri=3.3001 R3=4 368J B l1=0.0705 1. 0502 27. 5.

Ri=3.1436 21 SJ=0 O872 R,=2,4200 c 1;=0.57s1 1. 5004 52. 07

s.=0,2112 R1=2.7410 D 1,=0.44s5 1. 6860 33.

R,=4 06s2 0.2000 at 1.0000 s 04556 at 0.8062 R.=4 0243 1.1885 at 0.6500 E z,=0,s307 1.0344 10. a7

' Rio=8.1247

Ss=0,1041 s =0.1731 R1i=3.7706 F t1=0.3210 1. 0437 30. 00

R13=5,4137 22 S =0 502i R1:=10,5fi10 G t1=0.2550 1. 6278 4..

S.=0 02i4 R ,=21.0775 H t =0.640s 1. 60:10 17. 23

R a.5022 260552 at 1.0000 S 23.2050 0120.8062 20.7550 at 0.0500

NoTEs.-F.O.V.=44; F/#=F/l1.8; Zoom Magnification range=L000 to 0.6500,; E.F.L.=F1-oin 13.3585 to 12.7476. All dimensions are in inches.

Nd at V at Group Lens Radius Thickness Spacing 4,503 A. 4,500 A.

22.3261 at 1.0000 S'1= 24.2461 at 0.8500 R 6 2336 26.1064 at 0.6500

S; =0QZ86J R' =4.1518 B 2= .3772 1. 0502 27.82 51 R =3.4556

R. =2.6670 C I t =0.5104 1. 5004 52. 67

R a=2.5l11

S =0.3680 R1=3.2701 D 1' =0.3002 1. 6850 33.011

Ri=4.8112 0.5058 at 1.0000 s,= 0.6070 at 0.8500 R =4.2044 1.0057 at 0.0500 E t' =0.76l4 1.0341 111.37

R =11.7005 s'i=0.2734 Rn=4.5438 S';=0,l48i) F 1'1 =0.2l02 1.0137 30. .16

R'i:= 13.8506 G t. =0.2772 1. 6278 42. 40

R =40.5l86 S, 0 0002 I R15=13.9845 H 's= .8576 1. 6636 47. 23

is=-3.0800 25.0794 at 1.0000 S1o= 23.8073 at 0.8600 20.7093 at 0.6600

No'rEs.-F.O.V.=44; F/#=F/i1.8; Zoom magnification range=1.0(X); to 0.6600,; E.F.L.=Froni 13.4105 to 12,7803. All dimensions are in inches. 

1. A mechanically compensated zoom lens system consisting essentially of an axially movable front lens group and an axially movable rear lens group, each lens group consisting essentially of four air-spaced elements, the front lens group consisting essentially of, from the front to the rear, a first negative meniscus convex to the front, a second negative meniscus convex to the front, a third negative meniscus convex to the front and a positive meniscus convex to the front and the rear lens group consisting essentially of, from the front to the rear a first double convex element, a double concave element, a negative meniscus element concave to the front and a second double convex element.
 2. A mechanically compensated zoom lens system made substantially according to the following specifications:
 3. A mechanically compensated zoom lens system consisting essentially of an axially movable front lens group and an axially movable rear lens group, each lens group consisting essentially of four air-spaced elements, the front lens group consisting essentially of, from the front to the rear, a first negative meniscus convex to the front, a second negative meniscus convex to the front, a third negative meniscus convex to the front and a positive meniscus convex to the front and the rear lens group consisting essentially of, from the front to the rear a first double convex element, a first double concave element, a second double concave element and a second double convex element.
 4. A mechanically compensated zoom lens system made substantially according to the following specifications:
 5. A mechanically compensated zoom lens system made substantially according to the following specifications: 